linux-kernel - Re: [PATCH 43/43] KVM: nVMX: shadow pin based execution controls

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Date:   Fri, 14 Jun 2019 09:34:46 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        vkuznets@...hat.com
Subject: Re: [PATCH 43/43] KVM: nVMX: shadow pin based execution controls

On Thu, Jun 13, 2019 at 07:03:29PM +0200, Paolo Bonzini wrote:
> The VMX_PREEMPTION_TIMER flag may be toggled frequently, though not
> *very* frequently.  Since it does not affect KVM's dirty logic, e.g.
> the preemption timer value is loaded from vmcs12 even if vmcs12 is
> "clean", there is no need to mark vmcs12 dirty when L1 writes pin
> controls, and shadowing the field achieves that.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
> ---

Reviewed-by: Sean Christopherson <sean.j.christopherson@...el.com>

>  arch/x86/kvm/vmx/vmcs_shadow_fields.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/x86/kvm/vmx/vmcs_shadow_fields.h b/arch/x86/kvm/vmx/vmcs_shadow_fields.h
> index 4cea018ba285..eb1ecd16fd22 100644
> --- a/arch/x86/kvm/vmx/vmcs_shadow_fields.h
> +++ b/arch/x86/kvm/vmx/vmcs_shadow_fields.h
> @@ -47,6 +47,7 @@
>  SHADOW_FIELD_RO(GUEST_CS_AR_BYTES, guest_cs_ar_bytes)
>  SHADOW_FIELD_RO(GUEST_SS_AR_BYTES, guest_ss_ar_bytes)
>  SHADOW_FIELD_RW(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control)
> +SHADOW_FIELD_RW(PIN_BASED_VM_EXEC_CONTROL, pin_based_vm_exec_control)
>  SHADOW_FIELD_RW(EXCEPTION_BITMAP, exception_bitmap)
>  SHADOW_FIELD_RW(VM_ENTRY_EXCEPTION_ERROR_CODE, vm_entry_exception_error_code)
>  SHADOW_FIELD_RW(VM_ENTRY_INTR_INFO_FIELD, vm_entry_intr_info_field)
> -- 
> 1.8.3.1
>